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1.
Gremigni  V.  Falleni  A. 《Hydrobiologia》1998,383(1-3):235-242
The female gonad of Platyhelminthes shows a wide variability in its anatomical and cellular organization and submicroscopic structure, and some characteristics may be useful for elucidating the questioned monophyly of some taxa and reconstructing the phylogenetic tree of the group. The morphological characters of the female gonad have been subdivided into three levels: macroscopic, microscopic and ultrastructural, and some examples with potential phylogenetic value are presented for each level. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

2.
Falleni  Alessandra  Lucchesi  Paolo  Gremigni  Vittorio 《Hydrobiologia》1998,383(1-3):215-226
The female gonad of Temnocephala dendyi and T. minor consists of a single germarium and two rows of vitellaria. It is enveloped by an extracellular lamina and accessory cells. Accessory cells are only peripherally located in the germarium while their cytoplasmic projections also fill the spaces between vitellocytes in the vitellarium. The main feature of oocyte maturation is the appearance of chromatoid bodies and the development of rough endoplasmic reticulum (R.E.R.) and Golgi complexes which appear to be correlated with the production of double-structured egg granules. The egg granules, which are localized in the cortical cytoplasm of mature oocytes, contain glycoproteins, are devoid of polyphenols and are similar in structure and composition to the cortical granules observed in some Digenea and Monogenea. Vitellocytes are typical secretory cells with well-developed R.E.R. and Golgi complexes which are involved in the production of shell globules and yolk. The multigranular pattern and the polyphenolic composition of the shell globules of the temnocephalids investigated are similar to those observed in other rhabdocoels, and in some Prolecithophora and Neodermata. This feature may represent a synapomorphy shared by these taxa. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

3.
The female gonad of Prorhynchus is heterocellular (neoophoran organization) and consists of an unpaired, elongate germovitellarium enveloped by a finely granular extracellular lamina. It is composed of a posterior germinative area where early oocytes are randomly associated with differentiating vitellocytes and a growth area with follicular organization. In each follicle a single oocyte is surrounded by a layer of vitellocytes. By electron microscopy, the oocytes showed features typical of non-vitellogenic germ cells; they had chromatoid bodies, annulate lamellae, lipid droplets and R.E.R. and Golgi complexes producing small granules with a multilamellar pattern. Vitellocytes showed features typical of secretory cells with the R.E.R. and Golgi complex developed to a great extent and involved in the production of type A and type B globules, respectively. We speculate that type A globules are shell-globules and type B globules are yolk. The structure, composition and role of vitellocyte globules of Prorhynchus are compared with those of homologous inclusions from other Platyhelminthes.Abbreviations A type A globule - B type B globule - ECL extracellular lamina - GC Golgi complex - L lipid - RER rough endoplasmic reticulum - O oocyte - V vitellocyte  相似文献   

4.
    
The female gonad of the land planarians Microplana scharffi and Microplana terrestris consists of two small germaria located ventrally in the anterior third of the body and of two ventro‐lateral rows of oblong vitelline follicles distributed between the intestinal pouches. Both these structures are enveloped by a tunica composed of an outer extracellular lamina and an inner sheath of accessory cells. Oocyte maturation is characterized by the appearance of chromatoid bodies and the development of endoplasmic reticulum and Golgi complexes. These organelles appear to be correlated with the production of egg granules with a fenestrated/granular content of medium electron density, about 4–5 μm in diameter, which remain dispersed in the ooplasm of mature oocytes. On the basis of cytochemical tests showing their glycoprotein composition, and their localization in mature oocytes, these egg granules have been interpreted as yolk. In the vitelline follicles, vitellocytes show the typical features of secretory cells with well‐developed rough endoplasmic reticulum and Golgi complexes involved in the production of eggshell globules and yolk. The eggshell globules, which appear to arise from repeated coalescences of two types of Golgi‐derived vesicles, contain polyphenols and, when completely mature, they measure about 1–1,2 μm in diameter and show a meandering/concentric content pattern as is typical of the situation observed in most Proseriata and Tricladida. Mature vitellocytes also contain a large amount of glycogen and lipids as further reserve material. On the basis of the ultrastructural features of the female gonad and in relation to the current literature the two species of rhynchodemids investigated appear to be closely related to the freshwater planarians belonging to the family Dugesiidae. J. Morphol. 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

5.
Peroxisomes in three forms of vertebrate kidney (pronephros, mesonephros, and metanephros), as permanent or provisional kidney, are summarized concerning their ultrastructure and developmental changes. Because the peroxisome is known to be diverse in mammalian metanephros, and species difference is its distinctive feature among cell organelles, information should be obtained on each kidney of each species. The ultrastructural and biochemical features of peroxisomes have at least been partly delineated in the metanephros and mesonephros, but nothing is known about the pronephros. Ultrastructural studies of the metanephric peroxisomes are present in mammals, birds, and reptiles, but information on their development is restricted to mammals and birds. As for the mesonephric peroxisomes, both ultrastructural and developmental data have been accumulating on mammals and amphibians, and ultrastructural information is present on fishes, but not on birds and reptiles. At present, studies on peroxisomes of provisional kidney have been restricted to mammalian mesonephros. The common features of renal peroxisomes previously examined are that they are spherical cell organelles with a single limiting membrane in ultrastructure, and are positive for catalase. Information on the ultrastructure and enzymes is not sufficient at present for comparing the ontogenesis of renal peroxisomes with their phylogenesis. Part of this study appeared as an original paper (11), and was presented as a poster at the International Symposium/CREST Research Conference, Peroxisome: Biogenesis, Function and Disease.  相似文献   

6.
三种蚤生殖系统发育的细微结构:雌性生殖腺的发育   总被引:1,自引:3,他引:1  
漆一鸣 《昆虫学报》1984,(2):152-159
本文研究的缓慢细蚤Leptopsylla segnis (Schonherr,1811),不等单蚤Monopsyllus anisus (Rotbschild,1907)和猫栉首蚤指名亚种Ctenocephalides felis felis (Bouchè,1835)均采自贵阳市区,鼠、猫宿主体上。通过饲养与繁殖,制作从三龄幼虫至成虫成熟各发育时间的连续切片。预察了各发育时间生殖腺发育的内部结构变化,依据卵巢芽的发育、分化,末端最大卵母细胞形态和大小的变化,卵泡上皮细胞形态和大小的变化,卵泡间组织的出现,卵黄的产生、积累及卵壳物质的分泌等,将雌性生殖腺的发育分为四期10个阶段,并对雌性生殖腺发育内部结构的变化,雌蚤卵黄沉淀初期的“空位现象”等进行了分析析和讨论。  相似文献   

7.
蝗总科昆虫雌性下生殖板及系统发育关系研究(直翅目)   总被引:13,自引:0,他引:13  
在对蝗总科103种蝗虫雌性下生殖板进行形态学研究的基础上,对蝗总科8个科以及斑腿蝗科的稻蝗属,伪稻蝗属,拟凹背蝗属,卵翅蝗属和剑角蝗科的卡蝗属,选择导卵器正面观形态等15个性状,以蚱总科为外群确定性状的极性和状态,用Henning86V1.5软件对它们的系统发育关系进行地序分类研究。结果支持刘举鹏在1991年依蝗卵结构所提出的蝗总科分类系统,同时结果也表明蝗属,伪稻蝗属,拟凹背蝗属,卵翅蝗属和卡蝗  相似文献   

8.
The Neoophora is characterized by the presence of complex female gonads composed of both germaria and vitellaria. The vitellaria are made up of vitelline cells that differentiate to produce and accumulate reserve substances (proteins, lipid, glycogen) and precursors of the egg capsule or cocoon shell (phenolic proteins). A comparative ultrastructural and cytochemical investigation of shell-forming globules from the vitelline cells of some neoophoran platyhelminths shows that the internal structures of the shellforming globules can be grouped into two (or three) main types. In the first, globule content is characterized by a more or less homogeneous electron-dense substructure evidently arising from repeated coalescence of small vesicles produced by the rough endoplasmic reticulum and Golgi complex. A variant of this type of globule shows intermingling (or concentric) electron-dense and translucent areas producing a pattern resembling brain convolutions (convoluted pattern). The second type of shell-globule structure shows a multigranular pattern, presumably resulting from repeated fusions of Golgian vesicles followed by incomplete coalescence of the electron-dense content. Comparison of shell-globule structure in different taxa could be useful in elucidating some complex and still-unclear phylogenetic relationships among Platyhelminthes.  相似文献   

9.
    
The cytoarchitecture of the female gonad of the endosymbiont umagillid Syndesmis patagonica has been investigated using electron microscopy and cytochemical techniques. The female gonad consists of paired germaria and vitellaria located behind the pharynx in the mid‐posterior region of the body. Both the germaria and the vitellaria are enveloped by an outer extracellular lamina and an inner sheath of accessory cells which contribute to the extracellular lamina. Oocyte maturation occurs completely during the prophase of the first meiotic division. Oocyte differentiation is characterized by the appearance of chromatoid bodies and the development of endoplasmic reticulum and Golgi complexes. These organelles appear to be involved in the production of round granules, about 2–2.5 μm in diameter, with a homogeneous electron‐dense core surrounded by a granular component and a translucent halo delimited by a membrane. These egg granules migrate to the periphery of mature oocytes, are positive to the cytochemical test for polyphenol detection, are unaffected by protease and have been interpreted as eggshell granules. The mature oocytes also contain a small number of yolk granules, lipid droplets, and glycogen particles scattered throughout the ooplasm. The vitellaria are branched organs composed of vitelline follicles with vitellocytes at different stages of maturation. Developing vitellocytes contain well‐developed rough endoplasmic reticulum and small Golgi complexes involved in the production of eggshell and yolk globules. Eggshell globules are round, measure 4–5 μm in diameter, and have a mosaic‐like patterned content which contains polyphenols. The yolk globules, 2–3 μm in diameter, show a homogeneous protein content of medium electron density, devoid of polyphenols, and completely digested by protease. The mature vitellocytes also contain glycogen as further reserve material. The presence of polyphenolic eggshell granules in the oocytes and of polyphenolic eggshell globules with a mosaic‐like pattern in the vitellocytes have been considered apomorphic features of the Rhabdocoela + Prolecithophora. J. Morphol. 275:703–719, 2014. © 2014 Wiley Periodicals, Inc.  相似文献   

10.
Testicular ultrastructure was studied in Barbus longiceps, Capoeta damascina and their natural hybrid. The testes of these teleosts belong to the unrestricted or lobular type. Germ cell morphology is similar in the parental males. In the hybrid, spermatogenesis does not extend beyond the pachytene of the first meiotic division, probably due to the unsuccessful pairing of the homologous chromosomes. Hybrid testes are occupied mainly by degenerating primary spermatocytes, at the leptotene and pachytene stages. In both parents and the hybrid, Sertoli and Leydig cells are characterized by the presence of granular endoplasmic reticulum and of mitochondria with tubular cristae. Due to the arrest of spermatogenesis, the male germ cell protective barrier is absent in the hybrid. Germ cell nuclear size was measured by a computerized analysis system, using light-microscopy images. In the parents and the hybrid, germ cells attain a uniform inter-individual nuclear size when they reach the first meiotic prophase. The nuclear size of primary spermatocytes is similar among the three groups of fish, possibly reflecting their close genetic relationship.  相似文献   

11.
In the just-metamorphosed juveniles of Ciona intestinalis, a round mass of tissue debris derived from the resorbed tadpole tail is situated in the broad space enclosed by the peritoneal membrane and the epidermis around the ventral side of the esophagus. In living juveni es, the origin of the gonad rudiment was traced back to the mass of tissue debris. Electron microscopically, the round mass was a clump of irregular-shaped phagocytotic cells engulfing degenerated cell fragments. On the surface of the cell clump, a small number of singly occurring round cells were found and identified as primordial germ cells on the basis of morphological continuity to obvious germ cells in later stages. Presence of nuage around the nucleus characterized the germ cells. In a few days the germ cells assembled to form a solid slender body (gonad rudiment) together with smaller somatic cells. The gonad rudiment left the space around the esophagus, moving into the narrow mesenteric space connecting the stomach and intestine on the fourth day after metamorphosis. It gradually increased in size by proliferation of the germ cells and somatic cells. The solid gonad rudiment changed into an oval vesicle with an eccentrically located cavity on about the seventh day after metamorphosis. The vesicle comprised a thinner wall made of a simple epithelium without germ cells and a thicker wall containing germ cells and somatic cells.  相似文献   

12.
    
Summary

Female polyps of Cirrhipathes cfr. anguina were collected in August 2007 from the coral reef of Siladen Island in the Bunaken Marine Park (North Sulawesi, Indonesia). The primary transverse mesenteries, which separate the adjacent lateral tentacles from one another, were filled with oocytes developing within the mesoglea. Cross-sections of the oral region revealed that young gametes were located both at the emergence of the primary transverse mesenteries from the gastroderm lining the coelenterons, and at the point where the mesenteries were linked to the pharynx. By contrast, at a lower level, where the mesenteries gave rise to mesenterial filaments, young gametes were limited to the initial part of the mesenteries. Oocytes were lodged in individual chambers, and were separated from one another by mesogleal elements. On occasion, oocytes were found in proximity to cells with short microvillous-like processes that interdigitated with those emerging from the oocyte surface. Oocytes varied in size according to the stage of the vitellogenetic process, the largest measuring 125 μm in diameter. Their cytoplasm was enriched with inclusions of three main kinds: lipids, yolk and both rod- and ovoid-shaped bodies. These bodies were characterized by an electron-dense core with a dotted appearance, surrounded by a sequence of tightly-packed fibrils arranged in parallel fashion. These bodies pushed the oocyte membrane slightly outwards, giving rise to irregular “spiny” protrusions. In addition to the microvillous-like extensions, oocytes also showed short lobose pseudopodia; both are probably involved in nutrient uptake. No other membrane specializations were observed in the oocytes, the general morphology of which seemed to be coherent with the assumption that they had reached their final stage of growth. Investigations on the reproduction of the black coral may provide insights into the feasibility of transplanting fertile colonies into areas where they have been decimated by anthropogenic pressure.  相似文献   

13.
    
The ultrastructure of the female gonad of the land planarian Geoplana burmeisteri was investigated by means of electron microscopy and cytochemical techniques. It consists of two small germaria located ventral to the intestine and of two irregular, lateral rows of vitelline follicles, both enveloped by a tunica composed of an extracellular lamina and an inner sheath of accessory cells. Accessory cell projections completely surround developing oocytes and vitellocytes. The main feature of oocyte maturation is the appearance of chromatoid bodies and the development of the rough endoplasmic reticulum (RER) and Golgi complexes. These organelles appear to be correlated with the production of egg inclusions of medium electron density, about 1.5-1.8 microm in diameter, which remain scattered in the ooplasm of mature oocytes. On the basis of cytochemical tests demonstrating their glycoprotein composition, these inclusions were interpreted as residual yolk globules. Vitellocytes are typical secretory cells with well-developed RER and Golgi complexes that are mainly involved in the production of yolk globules and eggshell globules, respectively. Eggshell globules appear to arise from repeated coalescence of small Golgi-derived vesicles and, at an intermediate stage of maturation, show a multigranular pattern. Later, after vesicle fusion, they reach a diameter of 1.3-1.6 microm when completely mature and show a meandering/concentric pattern, as is typical of the situation seen in most Proseriata and Tricladida. The content of yolk globules is completely digested by pronase, while the content of eggshell globules is unaffected. Mature vitellocytes contain, in addition, a large quantity of glycogen and lipid droplets as further reserve material. On the basis of the ultrastructural characteristics of the female gonad described above and in relation to the current literature, we conclude that G. burmeisteri appears to be more closely related to the freshwater triclads, in particular to members of the Dugesiidae, than to the marine triclads.  相似文献   

14.
豌豆潜蝇姬小蜂雌蜂触角感器的扫描电镜观察   总被引:3,自引:1,他引:3  
应用扫描电镜观察豌豆潜蝇姬小蜂Diglyphus isaea Walker雌蜂触角感器,包括Bhm氏鬃毛、感觉孔、单孔毛状感器、多孔片状感器、锥形乳头状感器、厚壁化学感器、薄壁化学感器和毛状感器8种感器,分别对这8种感器的形态特征进行详细描述,并推测其可能的功能;还对有关的潜蝇姬小蜂生物学特性做深入的分析和讨论。  相似文献   

15.
    
The female genital structures of Macrocyclops albidus (Cyclopidae, Eucyclopinae) were studied using light and electron microscopy. The results confirm that the exterior genital area shows only a copulatory pore, located anteromedially on the ventral face of the genital double-somite, and paired gonopores (not directly visible), situated laterally under the P6 plates. An internal seminal receptacle, composed of several parts, is connected to the gonopores by ventro-lateral cuticular extensions or seminal ducts. The lateral site of communication shows a complex set of connections between the seminal receptacle and the oviducts (via the egg-laying ducts). The structure until now designated as ‘transverse ducts’, visible by transparency on the ventral face, is in fact constituted of internal cuticular thickenings resulting of the fusion of the 6th thoracic somite and the 1st abdominal somite forming the genital double-somite and appearing externally as a part of the suture line; the term ‘suture cord’ is proposed to designate it. The functioning of the system is explained.  相似文献   

16.
鲟鱼类系统进化的研究现状   总被引:7,自引:0,他引:7  
本文回顾了鲟鱼的分类、起源、性骼系统发育、细胞遗传学的研究、线粒体部分基因的研究,阐述近年年来鲟鱼系统进化的研究现状,从鲟鱼系统进化关系可以推测出尚未有核型报道的S.allnis,S.sullkusi和P.hermanni 3种鲟鱼可能为四倍体,讨论了当前鲟鱼类系统进化研究中存在的问题。  相似文献   

17.
    
The female genital system of the oviparous peripatopsid Ooperipatellus decoratus consists of an ovary, oviducts equipped with receptacula seminis and additional pouches, uteri, and a vagina. It is examined using transmission and scanning electron microscopy. The ovary is made up of paired ovarian tubes united anteriorly and posteriorly and differentiated into a sterile dorsal part and a fertile ventral part with exogenous oocytes. Fertilization presumably occurs in the oviducts once the oocytes pass the receptaculum seminis. Although the receptacula seminis have been reported to occur in juvenile O. decoratus females only, the present study reveals that they are present in adult females as well. Their wall consists of a cuboidal epithelium covered with a thin collagen-muscle layer. The additional pouches are projections of the oviducts facing the receptacula seminis. They are distally closed to the haemocoel by a flattened epithelium and lack external muscle cells. A thin collagen layer is only found proximally. The uteri are characterized by a columnar epithelium with folded cell membranes allowing extension of the uteri, thus facilitating the passage of the large uterine eggs towards the vagina. Another dominating feature of the uteri is a distally increasing secretory production, which probably contributes to chorion development. Cilia occurring along the entire length of the uteri are considered to assist in the transport of eggs towards the vagina.  相似文献   

18.
    
Abstract. Previous studies have shown variable patterns of paternity after multiple mating, and also variation in sperm storage among individuals of Arianta arbustorum , which suggests that the spermatheca may influence paternity in this promiscuous land snail. To identify possible morphological correlates of sperm manipulation, we investigated arrangement and ultrastructure of the muscles of the spermatheca. The musculature surrounding the 2–9 spermathecal tubules is arranged in a complex three dimensional network. In addition, each tubule has a thin sheath in which longitudinally oriented cells make up the innermost layer. Usually, the smooth muscle cells are enclosed by connective tissue. Only occasionally is direct muscle-muscle contact established through dense plaques. The short thick filaments, their small diameter, the relatively weak development of the tubular system and sarcoplasmic reticulum, and the low density of mitochondria indicate that the muscle cells contract relatively fast but with little strength, that they recover slowly, and have low endurance. A single muscle cell may be innervated by several axons and one axon may contact several muscle cells. Combining evidence of the present paper and a foregoing investigation on the spermathecal epithelium, we suggest that the main function of the spermathecal muscles is to expel sperm stored for fertilization, while the ciliation of the common duct is probably responsible for the distribution of sperm among the tubules.  相似文献   

19.
盛茂银  陈庆富   《广西植物》2007,27(3):440-443
用压片法对原产贵州的六种淫羊藿属植物的根尖有丝分裂中期染色体核型进行了比较研究。结果表明:这6种淫羊藿在核型上基本相同,都有1对中间随体染色体,而且都为对称核型。箭叶淫羊藿、粗毛淫羊藿、巫山淫羊藿、黔北淫羊藿、四川淫羊藿的核型公式均为6m(2SAT)+6sm,而黔岭淫羊藿的为8m(2SAT)+4sm。  相似文献   

20.
Brockmann, C., Mummert, R., Ruhberg, H. and Storch, V. 1999. Ultrastructural investigations of the female genital system of Epiperipatus biolleyi (Bouvier 1902) (Onychophora, Peripatidae). — Acta Zoologica (Stockholm) 80: 339–349. The female genital system of the neotropical peripatid Epiperipatus biolleyi was examined using transmission and scanning electron microscopy. Special attention is given to the two accessory organs of the paired oviducts: the receptacula seminis and the ovarian funnels (Ovarialtrichter). The latter occur only in the Peripatidae, whereas receptacula seminis may also be present in the Peripatopsidae, the only other family in the Onychophora. The ovarian funnels of E. biolleyi are thin-walled and closed from the haemocoel. This trait has also been reported from Epiperipatus trinidadensis, Macroperipatus torquatus, and Eoperipatus weldoni, whereas other peripatids have ovarian funnels which have been reported to open into the haemocoel. The occurrence of artificially opened ovarian funnels, caused by tissue rupture during specimen preparation, is discussed. The presence of spermatozoa both in the receptaculum seminis and in parts of the uterus of the female examined in this study supports the hypothesis that in E. biolleyi insemination of juvenile females occurs directly via the genital opening. The female contained one unstalked cleavage embryo in each uterus horn. Two features of the uterus were found to be unique to E. biolleyi: (1) a second cell layer overlying the uterine epithelium with a pronounced secretory activity (2) embryos are enclosed in a noncellular coat interspersed with numerous transport vesicles.  相似文献   

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